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IEEE Transactions on Applied Superconductivity

Deep sub- mu m low-T/sub c/ Josephson technology: the opportunities and the challenges

M. B. Ketchen

Published Mar 1, 1993• 8 citations
Publisher

Abstract

It is suggested that the possibility now exists of highly leveraging existing semiconductor technology to explore submicron Josephson technology. Some of the opportunities and challenges of such an undertaking are discussed in the context of superconducting quantum interference devices (SQUIDs) and digital applications. In the area of digital Josephson technology, a 50-100-ps cycle-time 64-b RISC (reduced instruction set computer) microprocessor is proposed as a long-term goal. While it is unlikely that one will see a sub-100-ps system like this in the near term, research results supporting its feasibility may ultimately help build the case for the resources needed to produce it. Fabrication has been and will probably continue to be an impediment to the exploration of submicron and deep submicron Josephson technology. Coupling to existing semiconductor fabrication capability should help considerably in this area and should help to lay the groundwork for eventual manufacturing of submicron Josephson products.>

DOI
10.1109/77.233527

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It is suggested that the possibility now exists of highly leveraging existing semiconductor technology to explore submicron Josephson technology. Some of the opportunities and challenges of such an undertaking are discussed in the context of superconducting quantum interference devices (SQUIDs) and digital applications. In the area of digital Josephson technology, a 50-100-ps cycle-time 64-b RISC (reduced instruction set computer) microprocessor is proposed as a long-term goal. While it is unlikely that one will see a sub-100-ps system like this in the near term, research results supporting its feasibility may ultimately help build the case for the resources needed to produce it. Fabrication has been and will probably continue to be an impediment to the exploration of submicron and deep submicron Josephson technology. Coupling to existing semiconductor fabrication capability should help considerably in this area and should help to lay the groundwork for eventual manufacturing of submicron Josephson products.>
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Scaling of niobium RSFQ integrated circuit technology to deep submicron dimensions (linewidths of 300 nm or less) should permit increased clock rate (up to 250 GHz) and increased areal density of Josephson junctions (up to 1 million junctions/cm/sup 2/), without the need for external shunt resistors. It is shown how existing circuit layouts can be scaled down to these dimensions, while maintaining the precise timing essential for correct operation. Additional issues related to the practical realization of such circuits are discussed, including effects of self-heating and models for the generation and propagation of sub-ps single-flux-quantum pulses.
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